C3750e-universalk9-mz.150-2.se11.bin -

: Support for advanced routing protocols like OSPF, EIGRP, and BGP (depending on the license). StackWise Plus Support

If you are moving from a very old 12.2(xx) release, check the Release Notes for Catalyst 3750-E to ensure there are no intermediate bootloader requirements. c3750e-universalk9-mz.150-2.se11.bin

: The version. This is a very mature, "Extended Maintenance" release from the 15.0 SE train, often considered the most stable "final" version for these series. The Role of 15.0(2)SE11 : Support for advanced routing protocols like OSPF,